Hermes

"Hermes exited with code -4058. Check your model configuration and API key."

Last checked

The error

Error: spawn C:\Users\<you>\.hermes\hermes-agent\venv\bin\python ENOENT
Error: Hermes exited with code -4058. Check your model configuration and API key.

Quoted by several Windows users in issue #98 of the fathah/hermes-desktop project (May 2026). The message is built in that app's src/main/hermes.ts.

Despite the wording, this is not a model or API key problem. The message comes from the community Hermes Desktop companion app, and -4058 is the Windows file-not-found code: the app tried to start Hermes's Python and nothing was at that path. Update the companion app, confirm hermes --version works in PowerShell, and reinstall Hermes Agent if it does not.

Why it happens

The community Hermes Desktop app (an open-source companion, separate from the official Nous Research Desktop) launches Hermes Agent's Python as a child process. When that file is missing, Node.js reports ENOENT, which is exit code -4058 on Windows, and the app adds a generic hint about model configuration.

  1. The app looked for a Linux-style venv\bin\python on Windows, where the interpreter lives at venv\Scripts\python.exe. Current releases use the Scripts path.
  2. The Hermes Agent install never finished, for example when the installer hung on a prompt, so the venv does not exist.
  3. An update or reinstall moved or removed the venv the app points at.

The fix

  1. 1 Update the community Hermes Desktop app to its latest release.
  2. 2 In PowerShell, run hermes --version to confirm Hermes Agent is installed.
  3. 3 If it is missing or broken, run hermes update, or reinstall with the official PowerShell installer.
  4. 4 Restart the companion app and send a message again.
hermes --version

Still failing?

  • Read the line above the -4058 message: it names the exact path the app tried to start.
  • If you use the official Hermes Desktop from Nous Research instead, use its Repair install button.

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Frequently asked questions

Should I change my API key?

No. The app never got as far as calling a model. Fix the missing Python first; your key is probably fine.

Is this the official Hermes Desktop?

No. This message comes from a community companion app. The official Desktop app from Nous Research shows different startup errors, such as Hermes couldn't start.

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